Bruce Willis must really like projects that muck with time or at least involve confrontations between past and present: from his first major feature, “Sunset” (old guy vs. young guy, real West vs. more modern myths of the West) through “Lucky Number Slevin” with its deceitful layers of narrative, to (obviously) “Pulp Fiction.” One might even (in a stretch) include his voice-over for “Look Who's Talking,” whose central joke was derived from the clash between Willis' adult voice and the adorable moppet it represented.

Both the underappreciated “The Kid” and arguably overappreciated “Twelve Monkeys” involved actual time travel. So let's consider “Looper” — intelligently written and directed by Rian Johnson (“Brick”) — the third of Willis' time-travel trilogy. This time around it's retired hit man Joe (Willis) being sent into the past to be murdered by his younger self (Joseph Gordon-Levitt).

Old Joe doesn't show up on screen for almost half an hour; prior to his arrival, we cleave strictly to Young Joe's point of view in the year 2044. Thankfully, this includes a voice-over, which gives the filmmaker a chance to establish the exact rules of this universe's time-bending. The technique is invented in 2074; because of the danger of Mr. 2074 changing something in 2044 that will affect 2074, it's use is highly prohibited, only used by the criminal world.

Even those mugs are afraid of messing up the current (2074) world, so — rather than exploiting future knowledge of sports events or stock market trends — they use it exclusively for one minimum-impact purpose: shipping their enemies to a 30 years earlier reality to be killed immediately after arrival by assassins called Loopers. No corpses, no evidence. (Jeff Daniels plays the one man from the future alive in 2044 — the boss of the assassins.)

Of course, there's always the chance that a Looper will screw up or will hesitate after somehow realizing that his latest hooded victim is in fact his older self. At one point, we see a clever and disgustingly graphic demonstration of how that's likely to turn out.

Young Joe seriously considers killing Old Joe, while Old Joe is determined to guarantee things develop just the way he remembers, up to but not including his own death sentence. His plan is to eliminate the evil boss who in 2074 has ordered — will order? — his execution ... in 2044, when the boss is a 5-year-old. (Still following?)

Because of the inevitable paradoxes, time-travel movies almost never make complete sense, but Johnson works very hard here — harder than any other director of such stories I can think of — to preclude these problems by limiting the technology's capabilities. Still, as in last year's “Source Code,” there are moments when developments grow murky, particularly regarding emotions. And this emotional content is (curiously) more reminiscent of Chris Marker's “La Jetee” than was “Twelve Monkeys,” which claimed to be adapted from the Marker short. The emotions are less effective than in “La Jetee,” but “Looper” does go for somewhat the same spirit.

One minor annoyance: Toward the end, “Looper” seems to be heading in a certain plot direction ... but then doesn't, as though ghosts of an earlier, eventually rejected draft hadn't been completely eradicated. (Read either of Robert A. Heinlein's brilliant stories “All You Zombies” or “By His Bootstraps” to see the direction I'm referring to.)

Or maybe, driven by a long standing compulsion to work out the details of this kind of story, I'm just projecting needless messy complications on a well-worked-out structure. I'm going to have to see it a second time to make sure. But you can go see it just once and be guaranteed an engaging, entertaining time.

ANDY KLEIN is the film critic for Marquee. He can also be heard on “FilmWeek” on KPCC-FM (89.3).